Protease inhibitor from Moringa oleifera leaves: Isolation, purification, and characterization

► We report here the isolation, purification, and characterization of a protease inhibitor isolated from mature leaf extract of Moringa oleifera. ► Maximal inhibitor activity was recorded at pH 7 and at 40 °C. ► The inhibitor was stable over pH 5-10; and at 50 °C for 2 h. ► The low Ki value (1.5 nM) obtained indicated scope for utilization of M. oliefera protease inhibitor against serine proteases.